Nozzle braze backside cooling

Abstract

A nozzle vane includes a row of trailing edge apertures and cooperating inboard slots joined in flow communication with a mid-chord cavity. An outboard slot is spaced outwardly from a respective last one of the inboard slots, and outboard of a respective last one of the trailing edge apertures. The outboard slot extends behind a braze joint between the vane and a supporting band and is effective for backside cooling thereof.

Accordingly, what is desired to be secured Letters Patent of the United States is the invention as defined and differentiated in the following claims in which we claim:  
     
       1. A turbine nozzle comprising: 
       outer and inner bands having respective pairs of vane seats extending therethrough;  
       a pair of vanes having respective roots disposed in said vane seats, and fixedly joined therein by corresponding braze joints, and including opposite sidewalls joined together at opposite leading and trailing edges; and  
       each of said vanes further includes a last trailing edge aperture spaced inboard from a corresponding braze joint and disposed in flow communication with an outboard slot bridging said sidewalls and extending behind said braze joint for channeling cooling air from a mid-chord cavity of said vane to said last aperture for backside cooling said braze joint therealong.  
     
     
       2. A nozzle according to  claim 1  wherein said outboard slot extends substantially straight from said mid-chord cavity toward said trailing edge, and bends at an aft end thereof to cross behind said braze joint to terminate at said last apertured. 
     
     
       3. A nozzle according to  claim 2  wherein said vane roots are imperforate between said trailing edge and mid-chord cavity except for an inlet therethrough for said mid-chord cavity. 
     
     
       4. A nozzle according to  claim 3  wherein each of said vanes includes a pair of said last trailing edge apertures and cooperating pair of outboard slots at respective opposite root ends thereof for backside cooling said braze joints at both said outer and inner bands. 
     
     
       5. A nozzle according to  claim 4  wherein each of said vanes further comprises: 
       a row of trailing edge apertures, including said pair of last apertures adjacent said outer and inner bands; and  
       an array of inboard slots disposed between said pair of outboard slots in flow communication between said mid-chord cavity and respective ones of said trailing edge apertures.  
     
     
       6. A nozzle according to  claim 5  wherein each of said outboard slots terminates in common with an adjacent one of said inboard slots at a respective one of said last apertures. 
     
     
       7. A nozzle according to  claim 6  wherein each of said vanes further comprises a side outlet extending through one of said sidewalls in flow communication with a respective one of said outboard slots for discharging said cooling air therefrom. 
     
     
       8. A nozzle according to  claim 7  wherein said side outlet is disposed at said bend in said outboard slot, and exits said sidewall away from said braze joint. 
     
     
       9. A nozzle according to  claim 8  wherein respective ones of said side outlets are disposed through both sidewalls of said vanes. 
     
     
       10. A method of making said nozzle according to  claim 1  comprising: 
       forming said vanes with said last trailing edge apertures and cooperating outboard slots;  
       assembling said vanes and bands together; and  
       brazing said vanes at said roots to said bands without plugging said last apertures.  
     
     
       11. A method-of making said nozzle according to  claim 7  comprising: 
       forming said vanes with said last trailing edge apertures and cooperating outboard slots;  
       assembling said vanes and bands together; and  
       brazing said vanes at said roots to said bands without plugging said last apertures and said side outlet.  
     
     
       12. A nozzle vane including a row of trailing edge apertures and cooperating inboard slots joined in flow communication with a mid-chord cavity, and a pair of outboard slots spaced outwardly from respective last ones of said inboard slots at opposite ends of said vane and outboard of respective last ones of said trailing edge apertures. 
     
     
       13. A vane according to  claim 12  wherein each of said outboard slots terminates in common with an adjacent one of said inboard slots at a respective one of said last apertures. 
     
     
       14. A vane according to  claim 13  further comprising opposite sidewalls joined together at opposite leading and trailing edges; and said outboard slot extends between said sidewalls for backside cooling both said sidewalls near said trailing edge. 
     
     
       15. A vane according to  claim 14  wherein said outboard slots extend substantially straight from said mid-chord cavity toward said trailing edge, and bend at an aft end thereof to cross over to said last inboard slots at-said trailing edge. 
     
     
       16. A vane according to  claim 15  wherein said last apertures are spaced inboard from respective root ends of said vane for avoiding a braze joint thereat when brazed to outer and inner nozzle bands. 
     
     
       17. A vane according to  claim 16  further comprising a side outlet extending through one of said sidewalls in flow communication with a respective one of said outboard slots for discharging cooling air therefrom. 
     
     
       18. A vane according to  claim 17  wherein said side outlet is disposed at said bend in said outboard slot, and exits said sidewall for avoiding said braze joint. 
     
     
       19. A nozzle vane including a row of trailing edge apertures joined in flow communication with a mid-chord cavity by corresponding inboard channels bridging opposite sidewalls of said vane for discharging cooling air at corresponding flowrates through said apertures, and a pair of outboard channels bridging said vane sidewalls and spaced outwardly from respective last ones of said inboard channels at opposite ends of said vane and outboard of respective last ones of said trailing edge apertures, and said outboard channels terminating in common with respective ones of said last inboard channels. 
     
     
       20. A vane according to  claim 19  further comprising a side outlet extending through one of maid sidewalls in flow communication with a terminus bend of a respective one of said outboard channels for discharging cooling air therefrom.